Gastroesophageal reflux disease (GERD) is highly associated with a range of respiratory symptoms, arising from a variety of etiologies. The following commentaries on respiratory manifestations of GERD address evidence for a role of a vagally mediated bronchoconstriction reflex in the development of asthma; the direct effects of airway obstruction on lower esophageal sphincter (LES) pressure and reflux episodes; the mechanisms by which reflux may play roles in chronic cough and airway stenosis; the limited efficacy of laparoscopic antireflux surgery (LARS) in improving GERD-related respiratory symptoms; the search for a marker for microaspiration and reflux-induced airway disease; and the potential of proton pump inhibitor (PPI) treatment for patients presenting with asthma and GERD.

In patients with laryngopharygeal reflux (LPR), gastric contents exhibit retrograde flow into the upper aero-digestive tract, causing extraesophageal symptoms including chronic cough, hoarseness, indigestion, difficulty swallowing, globus pharyngis, and asthma. The following on laryngopharyngeal reflux includes commentaries on the use of patient-completed questionaires and anti-human pepsin antibodies and other non-invasive tests in diagnosis; the role of pepsin and acid in the etiologies of laryngeal cancers; and the application of proton pump inhibitor (PPI) therapy for the treatment of LPR.

BACKGROUND & AIMS: Use of proton pump inhibitors (PPIs) could predispose individuals to small intestinal bacterial overgrowth (SIBO) by altering the intraluminal environment and bacterial flora. There is controversy regarding the risk of SIBO among PPI users because of conflicting results from prior studies. A systematic review and meta-analysis were performed to evaluate the association between PPI use and SIBO, using objective clinical outcome measures.

METHODS: Clinical studies comparing SIBO risk among adult users of PPIs vs nonusers were identified in MEDLINE/PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, and the National Institutes of Health Clinical Trials databases through July 2012. Two reviewers independently extracted data on study characteristics and outcomes. The primary metameter was the odds ratio (OR) of SIBO among PPI users vs nonusers. Subgroup analyses were performed to examine the influence of study characteristics, such as SIBO diagnostic modality, on study outcome.

RESULTS: Eleven studies (n = 3134) met inclusion criteria. The pooled OR of SIBO in PPI users vs nonusers was 2.282 (95% confidence interval [CI], 1.238-4.205). No significant single large study or temporal effect was seen. Subgroup analysis revealed an association between SIBO and PPI use in studies that used duodenal or jejunal aspirate cultures to diagnose SIBO (OR, 7.587; 95% CI, 1.805-31.894), but no relationship was found between SIBO and PPI use in studies that used the glucose hydrogen breath test (OR, 1.93; 95% CI, 0.69-5.42). Funnel plot analysis identified 4 outlying studies, indicating the possible presence of publication bias.

CONCLUSIONS: PPI use statistically was associated with SIBO risk, but only when the diagnosis was made by a highly accurate test (duodenal or jejunal aspirate culture). Differences in study results could arise from the use of different tests to diagnose SIBO.

BACKGROUND/AIMS: Lubiprostone, a chloride channel type 2 (ClC-2) activator, was thought to treat constipation by enhancing intestinal secretion. It has been associated with increased intestinal transit and delayed gastric emptying. Structurally similar to prostones with up to 54% prostaglandin E2 activity on prostaglandin E receptor 1 (EP1), lubiprostone may also exert EP1-mediated procontractile effect on intestinal smooth muscles. We investigated lubiprostone's effects on intestinal smooth muscle contractions and pyloric sphincter tone.

METHODS: Isolated murine small intestinal (longitudinal and circular) and pyloric tissues were mounted in organ baths with modified Krebs solution for isometric recording. Basal muscle tension and response to electrical field stimulation (EFS; 2 ms pulses/10 V/6 Hz/30 sec train) were measured with lubiprostone (10(-10)-10(-5) M) ± EP1 antagonist. Significance was established using Student t test and P < 0.05.

RESULTS: Lubiprostone had no effect on the basal tension or EFS-induced contractions of longitudinal muscles. With circular muscles, lubiprostone caused a dose-dependent increase in EFS-induced contractions (2.11 ± 0.88 to 4.43 ± 1.38 N/g, P = 0.020) that was inhibited by pretreatment with EP1 antagonist (1.69 ± 0.70 vs. 4.43 ± 1.38 N/g, P = 0.030). Lubiprostone had no effect on circular muscle basal tension, but it induced a dose-dependent increase in pyloric basal tone (1.07 ± 0.01 to 1.97 ± 0.86 fold increase, P < 0.05) that was inhibited by EP1 antagonist.

CONCLUSIONS: In mice, lubiprostone caused a dose-dependent and EP1-mediated increase in contractility of circular but not longitudinal small intestinal smooth muscles, and in basal tone of the pylorus. These findings suggest another mechanism for lubiprostone's observed clinical effects on gastrointestinal motility.

This paper reporting on techniques for esophageal evaluation and imaging and drugs for esophageal disease includes commentaries on endoscopy techniques including dye-based high-resolution and dye-less high-definition endoscopy; the shift from CT to MRI guidance in tumor delineation for radiation therapy; the role of functional lumen imaging in measuring esophageal distensibility; electrical stimulation of the lower esophageal sphincter (LES) as an alternative to fundoduplication for treatment of gastroesophageal reflux disease (GERD); the morphological findings of reflux esophagitis and esophageal dysmotility on double-contrast esophagography; the value of videofluoroscopy in assessing protecting mechanisms in patients with chronic reflux or swallowing disorders; targeting visceral hypersensitivity in the treatment of refractory GERD; and the symptoms and treatments of nighttime reflux and nocturnal acid breakthrough (NAB).